Title :
Throughput enhancement of a slotted DS-CDMA ALOHA with packet combining
Author :
Annamalai, A. ; Wong, R.S.C. ; Bhargava, Vijay K.
Author_Institution :
Dept. of Electr. & Comput. Eng., Victoria Univ., BC, Canada
Abstract :
An adaptive time-diversity automatic repeat request scheme is investigated for a slotted DS-CDMA wireless data network over frequency selective Rayleigh fading channels. In the proposed technique, the receiver retains and processes all the retransmissions of a single data block using postdetection diversity combining rather than simply discarding the noisy packets. It is shown that packet combining is an effective mechanism for enhancing the network throughput and delay performance of a conventional DS-CDMA ALOHA, while sustaining a reasonable receiver complexity. This scheme is highly advantageous for systems which can tolerate a certain delay and operate over highly time-varying channels. We also examine the effects of forward error correction (FEC) coding and multipath intensity profile on channel utilization efficiency
Keywords :
Rayleigh channels; access protocols; automatic repeat request; channel capacity; code division multiple access; data communication; delays; diversity reception; error correction codes; fading; forward error correction; land mobile radio; multipath channels; packet radio networks; pseudonoise codes; radio receivers; spread spectrum communication; time-varying channels; adaptive time-diversity automatic repeat request scheme; channel utilization efficiency; delay; delay performance; forward error correction coding; frequency selective Rayleigh fading channels; multipath intensity profile; network throughput; packet combining; postdetection diversity combining; receiver complexity; retransmissions; slotted DS-CDMA ALOHA; throughput enhancement; time-varying channels; wireless data network; Automatic repeat request; Diversity reception; Fading; Forward error correction; Frequency; Intersymbol interference; Multiaccess communication; Personal communication networks; Spread spectrum communication; Throughput;
Conference_Titel :
Communications, Computers and Signal Processing, 1997. 10 Years PACRIM 1987-1997 - Networking the Pacific Rim. 1997 IEEE Pacific Rim Conference on
Conference_Location :
Victoria, BC
Print_ISBN :
0-7803-3905-3
DOI :
10.1109/PACRIM.1997.620312
